Question

se a²+ b²=100 e (a+b)²=196,calcule o valor de ab.

Answer 1

{a²+ b²=100
{(a+b)²=196

(a+b)²=196
a²+2ab+b²=196
100+2ab=196
2ab=96
ab=48

(a+b)²=196
a+b=√196
a+b=14

a+b=14

{a=14-b
{ab=48
(14-b)*b=48
14b-b²=48
-b²+14b-48=0
Δ=196-192=4

b=(-14+√4)/2*(-1)
b=(-12)/(-2)
b=6

a+b=14
a+6=14
a=14-6
a=8

Espero que tenha entendido!